Strand treatment process and apparatus



June 1968 R. K. STANLEY ETAL 3,386,142

STRAND TREATMENT PROCESS AND APPARATUS Filed July 22, 1966 INVENTORS. ROBERT K. STANLEY MALCOLM F, IRWiN United States Patent 3,386,142 STRAND TREATMENT PRGCESS AND APPARATUS Robert K. Stanley, Media, and Malcolm F. Irwin, Philadeiphia, Pa, assignors to Techniservice Corporation, Lester, Pa., a corporation of Pennsylvania Continuation-impart of application Ser. No. 401,160,

Oct. 2, 1964. This application July 22, 1966, Ser.

No. 567,245 The portion of the term of the patent subsequent to Oct. 18, 1983, has been disclaimed Claims. (Cl. 23-1) ABSTRACT OF THE DISCLOSURE The degree of crimp imparted to textile strands being fed continuously at constant rate into a stuffer crimping zone is controlled by setting the windup rate to desired constant value, without varying either rate in accordance with level or quantity of crimped strand in the chamber or otherwise synchronizing the rates.

This application is a cOntinuation-in-part of my copending application, Ser. No. 401,160 filed Oct. 2, 1964 now US. Patent 3,279,025 granted Oct. 18, 1966.

The present invention relates to an improvement in treatment of textile strands (as therein set forth) by compressive crimping thereof, as in a stuffer crimper.

Strand to be crimped is fed continuously at a preadjusted, essentially constant rate into a laterally confining region having an entrance and an exit to accumulate temporarily therein, the resulting strand accumulation therein being forced toward the exit by additional strand fed thereagainst at the entrance to the region, and crimped strand is withdrawn at an essentially constant rate, which is lower than the feed rate, and out of the exit by application of winding tension and essentially free from other tension application at and after the exit. The degree of crimp is controlled by adjusting the windup rate to different constant values.

It is conventional to crimp a textile strand compressively by feeding it by and between a pair of nip rolls into the entrance of a temporarily confining region, the exit of which is closed wholly or partially bysuitable means so that the strand accumulates therein under pressure and forces the entering strand to buckle into a modified zigzag or sawtooth crimped configuration. The construction is such that the strand accumulation eventually moves the closure means sufiiciently to escape from the confinement, whereupon the crimped strand may be wound up. Alternatively, the strand may be withdrawn lengthwise from the accumulation and be slid past the closure means, but that tends to alter the crimp non-uniformly or to remove it and is, therefore, undesirable. Depending upon structure and dependability of operation, the various types of closure means, and even the individual members of a single type, vary widely from one another, as does their effect upon the strand being crimped.

Conventional windup means and methods involve synchronization of strand windup rate and infeed rate. Alternatively, it is known to control the windup or the infeed rate (or both) in response to a sensing of the accumulation of crimped strand in either the confining region or an extension thereof or other holdup location. In all such cases the object is to prevent both over-accumulation of crimped strand, which might result in overflow and entanglement or breakage during windup, and underaccumulation thereof, which might withdraw uncrimped as well as crimped strand, resulting in serious non-uniformity of crimping treatment.

A primary object of the present invention is enhanced uniformity in compressive crimping of a textile strand.

Another object is simplification in strand windup in stutter-crimping apparatus and procedure.

A further object is improved control of the degree or extent of staffer-crimp in crimped textile strands.

Other objects of this invention, together with means and methods for attaining the various objects, will be apparent from the following description and the accompanying diagrams.

FIG. 1 is a schematic representation of the processing of a textile strand according to the present invention;

FIG. 2 is a front elevation, partly cut away, of apparatus of this invention in further detail, with strand shown passing therethrough;

FIG. 3 is a side elevation of the apparatus and strand of FIG. 2;

FIG. 4 is a plan of the apparatus of FIGS. 2 and 3, with the strand omitted for clarity; and

FIG. 5 is a plan, partly cut away to show the interior, of component apparatus taken at V-V on FIG. 3.

In general, the objects of the present invention are accomplished, in compressive crimping of a textile strand, by feeding the strand continuously at an essentially constant rate into a laterally confining region to accumulate temporarily therein and forcing the strand accumulation therein toward the exit therefrom by additional strand fed thereagainst at the entrance to the region, the strand accumulation being largely or preferably entirely unconfined ahead thereof and at the exit from the region, and withdrawing the strand therefrom at a somewhat lower constant rate, which can be adjusted within rather wide limits.

The practicability of using diverse but constant windup rates as well as a constant feed rate is astonishing because it would be expected that unless either the feed or windup rate were varied in strict accordance with the amount of crirnped strand accumulation in the confining region, or unless the respective rates were set at a particular fixed ratio to one another, the strand accumulation would either overflow or disappear entirely. The resulting ability to control the degree or extent of crimp in the strands is an unexpected additional benefit of this discovery.

FIG. 1 shows, schematically, strand l0 unwinding from conical package 11 to pass through guide 12 and successive pairs of rolls 13, 13 and 15, 15', with heater 14 for the strand intervening between the respective pairs .of rolls. Pair of nip rolls 1'7, 17 for feeding "the strand, normally at a fixed or constant rate, into chamber 18, part of the length of which is omitted from the view to conserve space of illustration, follow after strand-traversing means 16. Crimped strand 10 is wound up from the exit of the chamber onto cylindrical package 26 by grooved traversing drive roll 19.

FIGS. 2, 3, and 4 show stutter-crimping components and associated elements (FIGS. 2 and 3 only) of the same apparatus in front and side elevation and plan, respectively. Part of chamber 18 is cut away in FIG. 2 to reveal crimped strand 10' and accumulation thereof in bore 28 of the chamber, which is shown in the shape of a square cylinder. As in FIG. 1 the chamber in the elevational views of FIGS. 2 and 3 is broken away in vertical extent to conserve space in the drawing. Strand it after passing between nip rolls I5, 15' passes through strand-traversing means 16, which is slotted to receive it (as shown in FIG. 5) and into the nip of feed rolls 17, 17'. The latter rolls feed or stuff the strand into the entrance to the bore of the chamber, the front and rear walls of the chamber overlapping the front and rear faces of the rolls as far as the nip so as to ensure that all of the strand enters the chamber. As the strand accumulates in the chamber, the entering strand meets with resistance provided by the previously accumulated strand and buckles back and forth upon itself into a modified sawtooth or zigzag configuration or crimp. As more strand is fed continuously into the chamber the strand accumulation is forced along through the bore toward the exit therefrom.

The exit end of the chamber bore, located at the same level as the entrance in the embodiment shown in FIG. 1 and at a level vertically above the level of the entrance inthe embodiment (which may be otherwise the same) shown in FIGS. 2, 3, and 4, is unobstructed, as is the rest of the bore. Crimped strand is withdrawn at a constant or fixed rate, which is adjustable as desired, from strand accumulation 100 inside and is wound up onto bobbin or like package 20, which is rotated by contact with the surface of rotating drive roll 19. The drive roll is grooved helically from end to end, the groove reversing direction at each end, and thereby is adapted to tra verse the strand passing over it and through the groove on its way to the package. The adjustable constant-rate drive means for the self-traversing drive roll is conventional in design, and therefore, not shown. The same is true of drive means for the other rolls (some of which may not be driven at all), but the drive means for the feed rolls of the stuffer-crimper is shown in some detail to aid understanding thereof.

Chamber 13, into which the strand is stuffed and in which it assumes crimped configuration, is supported on the front wall of frame 22, which has an inverted U- shape in side elevation. Shafts 27, 2'7 for respective feed rolls 17, 17 are journaled in the front and rear walls of the frame and have intermeshing gears 37, 37 thereon behind the rear wall of the frame. Shaft 27' also has pulley 29 thereon. Motor 31 on the horizontal upper surface of the frame has shaft 32 on which is pulley 33. Belt 34- interconnects pulleys 33 and 29 to transmit rotational force to the gears, shafts, and the feed rolls themselves. The direction of rotation is such as to feed or stuff the strand by and between the counter-rotating feed rolls into the entrance of the chamber. As already indicated, the infeed rate is normally constant, although it may be adjustable to different rates to accommodate different strands or changes in operating conditions.

Strand-traversing means 16, through which strand 10 passes before entering the nip of feed rolls 1'7, 17, is a device for vibrating the strand back and forth along the roll nip, as is desirable to assure distribution thereof transversely of chamber 18 in which it accumulates in crimped configuration. The strand-traversing means, which appears in plan (partly in section) in FIG. 5, comprises housing 41, with aligned pair of slots 4-2 through its top and bottom walls near one side wall and in line with the strand path between the nip of rolls 1'5, and the center of the nip of feed rolls 1'7, 17'. Strand 10 is shown in solid lines centered in the slot, and in broken lines at two extreme positions nearer but not touching the ends of the slot, representing the extreme positions between which it vibrates about the center position. Extending from the top wall to the bottom wall of the housing on the opposite side of the pair of slots from the nearby end wall is post 43. Extending from the far end wall to the post and from the top to the bottom walls and attached to each by flexible margin 45 is diaphragm 44, which is parallel to the side walls and divides the major part of the housing into two compartments intercom municating only by way of the minor part or passageway between the post and the near end wall.

Solenoid 46, which has armature 47 attached to diaphragm 44, vibrates the diaphragm of strand-traversing means 16 at a suitable frequency, pulsing air back and forth between the two compartments past the strand traveling through the slotted minor part of the housing and vibrating it; the slots are sufliciently smaller in area than the passageway provided by that minor portion that only a small fraction of the moving air passes through the slots. As it vibrates, the strand travels back and forth along the nip of the feed rolls at the frequency of vibration, which may be the casual power frequency of fifty or sixty cycles per second or any other suitable frequency. At rates of travel of the strand at about a thousand yards or meters per minute or somewhat more, about a foot of the strand will accordingly travel past the strand-travers ing means during each cycle, all without touching any part of the strand-traversing means at any time.

When the apparatus of this invention is being started up, it is desirable to insert a rod or the like in the open end of chamber 18 to compress the first bit of strand being fed therein until a wad of crimped strand has accumulated, after which the accumulated strand may be allowed to be forced further in the chamber from the entering end, accumulating additional strand in crimped configuration behind it. Contrary to prior practice, no adder means is necessary to apply crimping back pressure to the strand during operation of the apparatus of this invention. Despite the lack of physical obstruction of the chamber the apparatus may be operated with the chamber in any desired orientation: e.g., horizontal as in FIG. 1, upright as in succeeding views, or at any intermediate angle, and even inverted (not shown).

As described, the strand is wound up from the accumulation in the chamber at a constant rate sufficient to keep it at some distance from the end of the chamber, usually within the range of from about two-thirds to about nine-tenths of the infeed rate. No means or method for synchronizing windup and feed rates is required, as the crimped strand will accumulate to a substantially constant level in the chamber, rising only slightly thereabove and falling only slightly therebelow, that level being determined by the windup rate and, of course, by the physical characteristics of the strand, as well as the temperature, wall friction, etc. Adjustment of the windup rate permits control of the degree or extent of crimp in the strand, the rate and the crimp varying inversely with respect to one another. Thus, a high windup rate produces a low level of strand in the chamber and a decreased degree of crimp, as compared with a high level of strand and increased crimp at a lower windup rate. Degree of crimp may be determined by any conventional method, and high crimp may be apparent in part as reduced crimp leg length, reduced angle between adjacent legs, increased crimp retention under tension, or any combination of these with one another, or possibly other crimp characteristics.

Strand crimped according to the present invention is free of undesirable irregularities attributable to uneven application of back-pressure by devices such as have been used in conventional stuffer-crimping apparatus or to uneven application of heat to the strand therein. Heater 14 heats the strand to desirable crimping temperature (e.g., 150350 F.), and the stuffing chamber may be heated, as by a heating jacket or by resistance coils in the chamber wall (neither shown) to preclude cooling or excessive cooling of the strand in the chamber, although it normally will be at an appreciable lower temperature at the exit (e.g., about F than at the entrance of the chamber. Any suitable means may be used to preheat the strand, such as hot rolls, a heated chamber, etc. instead of the illustrated bar type of heater. The actual heater temperature will depend upon the degree of lubrication (if any) and rate of travel of the strand (1000-2000 yards or meters per minute is preferred) as well as upon the strand composition and denier, the chamber composition, and the method of heating (conduction, convection, radiation, etc.). The stufiing chamber and other apparatus elements may be made of steel or other durable material. If desired, the inside wall of the chamber may be coated (e.g., with tetrafiuoroethylene) to reduce the coefiicient of friction, in which event the chamber should be lengthened accordingly. A chamber length of about a yard or meter (inner width about A inch for use with strands of about 10 to 100 denier) has proved suitable for nylon and other commonly available textile strand materials.

Although a preferred embodiment of this invention has been illustrated and described, by way of example, modifications may be made therein while retaining all or some of the advantages and benefits of the invention. Minor restriction or impedance of the strand in its path through the temporarily confining region, preferably in the vicinity of the feed rolls rather than further downstream, may be employed if desired. Parts may be added, combined, rearranged, or subdivided and equivalents be substituted without departing from the invention as defined in the following claims.

The claimed invention:

1. In stutter-crimping of a textile strand wherein the strand is fed continuously at an essentially constant rate into a laterally confining region having an entrance and an exit to accumulate temporarily therein and the strand accumulation therein is forced toward the exit by additional strand fed thereagainst at the entrance to the region, the improvement comprising withdrawing crimped strand from the accumulation thereof at a preadjusted, essentially constant rate, which is less than the feed rate and out of the exit by application of winding tension thereto and essentially free from other tension application at and after the exit.

2. The process improvement of claim 1 wherein the rate of withdrawal of the strand is within the range of from about two-thirds to about nine-tenths of the feed rate thereof.

3. The process improvement of claim 1 wherein the degree of crimp varies inversely with the withdrawal rate, and including the step of preadjusting the withdrawal rate to a constant value at which a preselected degree of crimp is obtained in the strand.

4. The process improvement of claim 1 wherein the strand is preheated before being fed into the laterally confining region to accumulate temporarily therein and is maintained at elevated temperature without absorbing further heat while in the confining region.

5. In stuifer-crimping of a textile strand, the improvement comprising feeding the strand continuously into the bottom end of a laterally confining region to accumulate temporarily therein, utilizing at least principally friction of lateral confinement of the strand accumulation therein to apply crimping backpressure to the strand being fed into the region, and removing strand therefrom by winding it up from the leading edge of the strand accumulation, controlling the degree of crimp imparted to the strand by adjusting the windup rate to a desired constant value, the windup rate being effective to maintain the top of the strand accumulation at a substantially constant level in the confining region.

6. The process improvement of claim 5 wherein essentially only the friction of lateral confinement of the strand is utilized to apply crimping back-pressure to the strand being fed into the confining region, the strand accumulation being unconfined ahead thereof, and wherein the strand is fed into the confining region at a constant rate within the range of about one-tenth to about one-half greater than the windup rate.

7. The process improvement of claim 5 wherein the strand is fed at a rate of at least a thousand yards per minute into the laterally confining region and the strand is wound up therefrom at a constant rate on the order of about one sixth less than the feed rate, which is also constant.

8. In apparatus for stutter-crimping a textile strand, a confining chamber having a bore therethrough open at both ends, a pair of nip rolls juxtaposed to the entrance end of the chamber bore and adapted to feed strand at a constant rate into the chamber bore to accumulate tempo rarily and be crimped therein, and means for withdrawing crimped strand therefrom at a constant rate that is lower than the feed rate, and excluding strand-impeding means at the exit end of the chamber bore and between the exit end and the withdrawing means spaced therefrom.

9. The apparatus of claim 8 including means for rotating the pair of nip rolls to feed strand upward into the chamber at a rate within the range of about one-tenth to about one-half greater than the windup rate.

10. The apparatus of claim 8 wherein the exit end and all intermediate parts of the chamber bore are free of closure and other impeding members, and the means for withdrawing crimped strand therefrom includes means for winding it up from the end of the strand accumulation exposed therein.

References Cited UNITED STATES PATENTS 3,046,633 7/1962 Ohashi et al. 28-1 3,279,025 10/1966 Stanley et al. 28-1 FOREIGN PATENTS 679,584 2/ 1964 Canada.

LOUIS K. RIMRODT, Primary Examiner. 

